Warm air furnace



Nov.. 26, 1935. R. w. KRUsE v 2,022,116

' WARM AIR FURNACE Filed March 22, 1934 2 Shets-Sheet l INVENTOR. fofrrnf. Mea/5E.

@Mpx ffl@- ATTORNEYS.

Nov. 26, 1935. R. w. KRUsE WARM AIR FURNAGE v2 Sheets-Sheet 2 I filedMarch 22, 1934 ATTORNEYS,

Patented Nov. 26, 1935 gozan ATENT OFFICE WARM AIR FURNACE Robert W.Kruse, Indianapolis, Ind., assignor to Kruse Company, Inc.,Indianapolis, Ind., a corporation Application March 22, 1934, Serial No.716,765

4 Claims.

This invention relates to a heat transfer plant, and particularly to aso-called warm air furnace. It is particularly adaptable forinstallations in residences, store rooms and the like.

The principal feature of the invention resides in theA arrangement ofthe air passages and tubes for rendering maximum heating efficiency witha minimum of space and expense in construction andinstallation. Byreason of the construction herein disclosed, the same heating eiciencyis obtained in .a furnace having substantially half the diameter of anVordinary warm air furnace. This is advantageous wherein space foraccommodating a furnace is at a premium. It also adds to the. appearanceof the furnace wherein the bulkiness of the usual warm air furnace isreduced toa compact, relatively small structure.

Another .advantage resulting from the relatively small and compactstructure resides in the ability of transporting a furnace, removing itand reinstalling it in other locations. Thus, the lessee of a store roomor residence may install a furnace of this character, and, upon movingto another location, may readily transport it.

The above advantages are accomplished by the provision of a plurality ofangularly disposed ,air tubes mounted in. swirling relation to thecombustion chamber, coupled with air swirling fins extendingrtherethrough and a baffle' for causing 1 the hot gases from the burnerto spread and pass upwardly about the angularly disposed air tubes. Airis projected by means of a blower through said tubes which gives it aswirling action, bringing it in direct contact with the heated walls ofthe tubes which in turn have .a maximum surface exposed to the'hotgases, as will be 'hereinafter more specifically described.

Other objects and features of the invention will be vreadily understoodfrom the accompanying drawings and vthe following Vdescription andclaims:` a

Fig. 1 is a front elevation of the furnace show- ,ing the combustionchamber in dotted lines associated with an air conditioning boxconnected with the intake. Fig. 2 is a central vertical section throughthe combustion chamber showing the air tubes in elevation. Fig. 3 is asection taken on the line 3-3 of Fig. 1. Fig. 4 is a central verticalsection through an air tube with a baffle plate mounted therein. Fig. 5is a plan View looking down on the furnace header.

In the drawings, there is illustrated a furnace having a relativelytall, cylindrical warm air casing III. In the bottom thereof there is afire box I'I having an opening I2 through Which the usual oil burner mayextend. (not illustrated) for gen- @rating heat in the usual andprescribed manner. The bottom portion of the casing surrounds the firebox in substantially spaced relation there- -to and is connectedtangentially to an air intake 5 passage I3 as illustrated in Fig. 3,said passage connecting with a blower chamber of an air conditioninghousing I4. Said blower chamber is provided with the usual blower (notillustrated) mounted on a shaft I5 and driven by a pulley I6 lo from anelectric motor I'I. Air is drawn into said chamber and forced throughthe passage I3 through air conditioning filters I8 from an air intakeI9.

Extending above the fire box there is a cylinl5 drical combustionchamber of steel with a flue opening 2| centrally disposed in the topthereof and a fire opening 22 centrally disposed in the bottom endsurrounding the top of the lire box. The flue opening 2l is connectedwith a flue-or 20 smoke pipe 23 which extends laterally through theupper wall of the furnace ,and supports a baille block 24 suspended inthe center of the nre box by a rod 25.

Mounted above the flue in the upper projecting 25 portion of the casing,there is an eccentric header 26 of greater diameter than the casing,from which the warm air leader pipes 2l project. The eccentric headerincorporates the advantageous effect of a leader pipe, while providing agreater 30 circumferential area for the pipe connections.

The purpose and advantage of the eccentric header 26 is to permit the`leader pipes 21 to be grouped on one side of the furnace wherein it isdesired, the said pipes extending in substan- 35 tiallyl one directiontherefrom. This is particularly applicable to installations wherein thefurnace is placed atthe rear of a store room or in a' corner lthereofand it is not feasible to extend the leader pipes from about its entireperiphery. 40 In such installations, greater efficiency is acquired byarranging the header eccentric of the furnace as disclosed, so that thehot air generated therein will be drawn to one side of the furnace andset up a. steady flow in that direc- 45 tion. This arrangement not onlyaccentuates the delivery of the warm air from one side of the furnace asis desirable in such installations, but permits of a greater number oflead pipes being connected with the one side thereof.

As illustrated herein, the bottom ledge or flange of the combustionchamber, indicated at 28 and surrounding the opening 22, is providedwith a plurality of circular openings or holes located concentricallythereabout, there being provided a total of fteen of such holesillustrated herein. The corresponding ledge or top of the combustionchamber is provided with seven outer holes and eight inner holesarranged concentrically, as illustrated in Fig. 3.

The holes in the bottom and top of the combustion chamber are connectedby air tubes 29, said tubes being formed of the usual heat-conductingmaterial and welded within their respective holes so as to provide anair-tight passage from under the combustion chamber through the` top. Asillustrated in Figs. 2 and 3, said tubes are arranged at an angle aboutthe central portion of the combustion chamber, leaving an opening ofapproximately the diameter of the baiile block 24. The direction of theangular position of the tubes is arranged to give the air passingtherethrough a swirling motion in the same direction as initiated by thetangential air duct I3. This will be noted from the arrangement of thetubes as indicated by arrows in Fig. 3.

Each tube is provided with a twisted or spiral baifle plate 3D, asillustrated in Fig. 4, for causing the air passing upwardly along theangularly disposed tubes to be twisted or swirled therein.

The combustion chamber is spaced inwardly from the casing by acorrugated spacer 3| extending therebetween through which air is causedto pass between the outer surface of the combustion chamber and thecasing for insulating the combustion chamber from the casing and causingthe former to remain relatively cool.

The individual air tubes have been indicated by letter in respect totheir relative position, as shown in Figs. 2 and 3, the fifteen tubesbeing lettered a to o, inclusive. It will be noted that they arerelatively spaced to provide room for sixteen tubes, one being left outto allow space for the hot water coil, not illustrated herein. Thus, thelower ends of the tubes 0` and a. are substantially spaced apart for thereception therebetween of such coil. n

Every alternate tube leads from the bottom of the combustion chamber tothe outer series of openings in the top thereof while the intermediatetubes lead from the single series of openings in the bottom o-f thecombustion chamber to the inner series of openings at the top thereof.

In operation, heat is generated in the fire box by any suitable type ofoil burner, the flame and hot gases extending upwardly through theopening 22 within the combustion chamber. Said hot gases are thereincapable of spreading out to the full diameter of the combustion chambersurrounding the air tubes 29. The baille block 24 forces the spreadingof the hot gases and prevents their passing directly through thecenterof the combustion chamber between the tubes to the flue. n

After spreading throughout the combustion chamber and around the tubes,passing the baille block, the hot gases are then permitted to escapethrough the flue 23, the heat conducted thereby having been largelyexpended upon the tubes and the top portion of the flue within the upperpart of the casing.

The numerous -air tubes afford a substantial radiating surface for theconduction of heat to the air passing through the tubes, and theirangular relation to the upward movement of the gases affects a bafflewhich increases the efficiency of heat interchange over such types ofradiating surfaces as extend directly in the line with the flow of hotgases.

This angular or swirling arrangement of the tubes further acts tovcreate a swirling action of .the hot gases so as to pass evenly aboutthe entire peripheral surface of the air tubes whereby the outer sidesthereof are heated to substantially the same extent as the inner sides,or, in other words, the entire surface of the tube is evenly heated bythe gases. Coupled with this effect upon the exchange of heat, thecurrent of air entering the casing tangentially effects its swirlingaction in the direction of the angular arrangement of the tubes so thatthe air is equally distributed throughout the fteen tubes hereinillustrated instead of passing more readily through the nearer tubesthan the more remote tubes.

In addition thereto, the spiral or twisted baiiles 30 extendinglongitudinally within the tubes cause the air passing therethrough to betwisted during its passage so as to increase the quantity of air cominginto direct Contact with the heat conducting wall of the tube. The vairthus lforcibly swirled upwardly through the tubes is discharged from thetop of the combustion chamber into the upper part of the casing in ahighly heated condition for eventual discharge from the top of thefurnace through the radially disposed leader pipes.

The swirling action created as above described has the further effect ofcausing an even distribution Vof warm air about the entire periphery ofthe upper portion of the furnace so as to cause a corresponding equaldistribution in its discharge therefrom.

By reason of the multiple air passage formed by the corrugated spacer 3|between the combustion chamber and casing, the exposed surface of thefurnace is maintained relatively cool, resulting in a minimum loss ofheat and controlled discharge from the upper portion thereof.

The invention claimed is:

1. A warm air furnace comprising a fire box, a cylindrical combustionchamber, a cylindrical casing enclosing and extending above and belowsaid combustion chamber to form an air heating chamber adjacent thereto,a plurality of air tubes extending through said combustionchambercommunicating through the top and bottom thereof with said airheating chamber, said tubes being spirally arranged about the axis of.said combustion chamberv to cause a spiral motion of the air passingtherethrough, and means for forcing air into-said casing tangentiallythereof for entering said tubes at the angle of their dispositionwhereby the air will be uniformly distributed therethrough.

2. A warm air furnace comprising a vertically disposed cylindricalcombustion chamber having central openingsV formed in the end walls forreceiving and discharging heated gases, a're box communicating with andbelow'the bottom opening, a flue for discharging said gasescommunicating with and above said chamber, said combustion chamber alsohaving a series of openings concentrically arranged about said centralopenings,

a plurality of spirally arranged air tubes extendc ingfrom the bottom tothe top of Vsaid combustion chamber and connecting the lower series ofopenings with their respective upper series Vin offset relation, acylindrical casing enclosing and extending from below said combustionchamber to a position thereabove and spaced therefrom to form an airheating chamber, and means for forcing air into the bottom portion ofsaid casing tangentially to said series of openings to cause the air tobe uniformly distributed to the respective openings and tubes connectedtherewith.

3. A warm air furnace comprising a vertically disposed cylindricalcombustion chamber having central openings formed in the end walls forreceiving and discharging heated gases, a fire box communicating withthe under side of said chamber, a ue for discharging said gasescommunieating with the upper side thereof, said combustion chamberhaving a single series of. openings concentrically arranged about thelower end of the chamber, and a double series of openings concentricallyarranged about the upper end thereof, a plurality of spirally arrangedair tubes extending from the lower to the upper end of said chamber,each of said tubes connecting a lower concentric opening with one of theupper concentric openings in offset relation, every other tube beingconnected with one series of upper concentric openings, and every othertube with the other series thereof, and means for causing air to passthrough said tubes.

4. A warm air furnace comprising a fire box, a cylindrical combustionchamber, a cylindrical casing enclosing said combustion chamber to forman air heating chamber adjacent thereto, means for causing air to passthrough said air heating chamber, an annular header of greater diameterthan said air heating chamber and positioned eccentrically thereof toprovide an overhanging section, a plurality of warm air pipes groupedtogether and communicating with the overhanging section of. said header,and means for causing a whirling motion of the air passing into saidheader for discharge through the overhanging portion thereof and thecommunicating group of air pipes.

ROBERT W. KRUSE.

